1. Field of the Invention
The present invention relates to an apparatus and method for controlling a portable device, and more particularly, to an apparatus and method for controlling a portable device that performs a plurality of functions respectively corresponding to a plurality of registered handgrip postures adopted by a user, the apparatus and method extracting probability information of an unregistered handgrip posture using probability information of a registered handgrip posture, comparing the probability information of the unregistered handgrip posture with the probability information of the registered handgrip posture, and determining whether to perform a predetermined function according to the results of the comparison.
2. Description of Related Art
Recent developments in integration technology have opened the way for the spread of various portable devices such as audio reproduction apparatuses (e.g., cassette tape players and CD players), wireless pagers, mobile phones, MP3 players, and portable game players.
In particular, mobile phones are no longer only tools for telecommunications but are also tools for providing a variety of multimedia functions such as a digital camera function and an MP3 player function.
Also, since the advent of storage media such as flash memories, portable devices such as MP3 players have become more widespread. Also, nowadays, customers pay more attention than ever to aesthetic aspects of portable devices as well as to functional aspects of the portable devices.
In view of these developments, a variety of materials have been used for portable device cases in order to meet various user demands, and an increasing number of customers are willing to buy additional portable device cases for their portable devices for protection and aesthetic purposes.
Examples of the materials of portable device cases include plastics, rubber, and leather. Portable device cases are generally manufactured to conform to the shape of portable devices that they are intended to encase. For example, portable device cases for mobile phones or MP3 players equipped with a liquid crystal display (LCD) window may include an opening or may be formed of a transparent material so that users can always examine a graphic interface displayed on the screen of the LCD window without removing the portable device cases. Nowadays, most portable devices are equipped with one or more buttons, and thus, an increasing number of portable device cases are designed to include an opening through which buttons on portable devices can be exposed.
With improvements in the design of portable devices and a diversity of user preferences regarding portable devices, portable devices equipped with a touch sensor have been developed and are increasingly replacing traditional portable devices equipped with a number of buttons that allow users to input user commands. Touch sensors may be comprised of a plurality of touch cells. When a user grabs, with his/her hands, a portable device equipped with a touch sensor comprising a plurality of touch cells, the touch cells are selectively chosen according to a handgrip posture adopted by the user. Then the portable device recognizes the pattern of a touch cell combination resulting from the selectively choosing, and performs a predetermined function according to the results of the recognition. In this manner, portable devices equipped with a touch sensor can facilitate the input of user commands.
FIG. 1 is a diagram illustrating a plurality of functions of a typical portable device equipped with a touch sensor that comprises a plurality of touch cells and a plurality of handgrip postures adopted by a user to perform the respective functions of the typical portable device. Referring to FIG. 1, the portable device may perform different functions according to a handgrip posture adopted by the user when the user holds the portable device with his/her hands. In other words, the pattern of a combination of touch cells chosen from the touch sensor by the user varies from one handgrip posture to another of the user. The portable device performs its functions according to the pattern of a touch cell combination resulting from the touching of the touch sensor by the user.
For example, when the user adopts a handgrip posture 10 for making a phone call, the portable device places a call to a predefined phone number or receives an incoming call. When the user adopts a handgrip posture 20 for inputting text messages using a short message service (SMS), the portable device displays a screen image for inputting text messages. When the user adopts a handgrip posture 30 for taking photos, the portable device performs a photographing operation. When the user adopts a handgrip posture 40 for playing games, the portable device displays a game screen.
As described above, portable devices equipped with a touch sensor determine a function corresponding to a touch cell combination that results from a handgrip posture adopted by a user, and performs a predetermined function according to the results of the determination. However, a user may adopt different handgrip postures, even for the same function of a portable device. Accordingly, portable devices may perform the same function for a certain range of handgrip postures in consideration of errors (deviations in handgrips) in predefined touch cell combinations. However, it is difficult to determine an allowable deviation range for a touch cell combination resulting from a registered handgrip posture. If the deviation range is too narrow, portable devices may not be able to perform functions in response to registered handgrip posture adopted by a user. Conversely, if the error range is too wide, portable devices may perform functions in response to unregistered handgrip postures.
Korean Patent Laid-Open Gazette No. 2000-071367 discloses a voice recognition system which generates variable rejection strictness as a function of at least one background noise level measured during training and noise signal measurements obtained during a recognition mode, and initiates a valid voice recognition operation. This voice recognition system prevents invalid utterances from being associated with a previously stored voice model and facilitates the detection of valid utterances.
The voice recognition system of Korean Patent Laid-Open Gazette No. 2000-071367, however, determines whether an input voice signal is valid simply based on the previously voice model without specifying signals in what range can be determined to be valid.
Given all this, it is necessary to develop methods and apparatuses which extract information regarding handgrip postures that can prevent a portable device from performing its functions from information regarding a limited number of registered handgrip postures and can thus prevent the portable devices from performing its functions in response to unregistered handgrip postures.